Heated Fluid Conduits, Systems and Methods

ABSTRACT

A heated fluid conduit has a body with a semi-conductive material disposed therein with an electrical power supply coupled to the conduit to provide a voltage across the conduit and a current therethrough, heating the fluid conduit. A fluid conduit heating system comprises a semiconductive sleeve disposed over a fluid conduit and an electrical power supply coupled to the ends of the sleeve to provide a voltage across the sleeve and a resulting current through the semiconductive sleeve, heating the sleeve and conduit Alternatively, one terminal of the electrical power supply is coupled to each end of the sleeve or conduit, and another terminal of the electrical power supply is coupled to the sleeve or conduit therebetween, to provide parallel heating circuits.

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates generally to fluid conduits such as hoses andtubes, more particularly to heated fluid conduits, and specifically tofluid conduits heated using semiconductive resistance heating.

Description of the Prior Art

Selective Catalytic Reduction (SCR) vehicles, referred to in Europe asEuro V vehicles, are diesel powered motor vehicles which are compatiblewith the use of an operating fluid to reduce emissions. Typically, theSCR vehicle has a urea tank, separate from the fuel tank, which is usedto carry an operating fluid such as an automotive urea solution, or thelike. Automotive Urea Solution (AUS) is a solution of high purity ureain de-mineralized water. AUS is stored in a urea tank of an SCR vehicleand is sprayed into the exhaust gases of the vehicle in order to convertoxides of nitrogen into elementary nitrogen and water. An SCR vehiclemay then advantageously satisfy various emission standards, such as theEuro V Emissions Standard.

Problematically, AUS freezes at a temperature of approximately minuseleven degrees centigrade. In order to ensure this method of reducingemissions in an SCR vehicle remains effective, the AUS needs to bemaintained in a liquid state to allow injection

SCR vehicles generally rely on a heating wire or the like, which may bemolded into or wrapped around the AUS hose or line to avoid freezing ofthe AUS. This is a rather inefficient and inflexible solution thatrequires a complete redesign of the fluid line to change its heatingproperties. Thus, to change the heating characteristics of an internalwire assembly, another production run of the hose must be produced andthe resistance per foot is changed when the hose is being extruded byeither changing the wire pitch, the wire size or adding more wires intothe system, or a combination of all three.

Also, oil drilling rigs are being operated in harsher environments asoil is drilled for in Alaska and the Arctic and Antarctica. It is nownot unusual for a rig to start up in minus sixty degree Fahrenheitweather. This cold weather has an adverse effect on equipment andhydraulic components on a drill rig. When starting up a hydraulicmachine at these cold temperatures it is not unusual for the seals torupture in valves and cylinders.

SUMMARY

The present invention is directed to fluid conduits, systems and methodswhich heat the fluid in the conduit (a hose, tube or the like). Thepresent invention is an electrically heated hose or other conduit thatwarms the fluid, before starting of the associated equipment to preventseal and component failure in hydraulic systems and/or that heats a urealine to prevent freezing of AUS. Embodiments of this hose may use asemi-conductive member of rubber or carbon fiber filament to create aresistive heating element within the hose, or a semi-conductive sleevedisposed about the hose. The hose can be used for many differentapplications for heating fluids that the hose is conveying. Thematerials that could be heated are hydraulic fluid, urea mixtures forcatalytic converters, grease lines, oil lubrication lines and/or thelike.

The semiconductive resistive heated hose is composed of an electricallyconductive rubber tube on the inside of the hose with a resistance of 2to 15 ohms per foot. It can also be composed of a composite, braided,carbon fiber tensile member or a carbon fiber sleeve that is pushed overthe hose assembly after the hose is constructed. This tube or sleeve,because of the electrical resistance, will heat up when a voltage isapplied to it in such a manner as to provide an electrical path. Theheat that is produced in the tube or sleeve will warm the internal fluidlowering the viscosity of the fluid and allowing it to flow withoutdamaging components. This tube or sleeve can be constructed into or on aconventional high pressure, wire reinforced, hydraulic hose, or thecarbon fiber can also be the tensile member of the hose. Whenelectricity is connected to the tube or sleeve electricity will flowthrough the tube of sleeve to ground and the result will be a heatedhose that is in contact with the fluid.

To facilitate operation of a semi-conductive heating sleeve it may beadvantageous to warm the couplings associated with the hose or tube. Ifthe couplings are not warmed with the hose, it may be difficult forfluid may to pass through the couplings. Therefore, it may beadvantageous to heat the couplings along with the hose, such as byextending the heating sleeve over the hose couplings. Also, preferably,the hose couplings are insulated and protected along with the wiringproviding power to the heating sleeve.

Hence, in accordance with embodiments of the present invention a methodfor providing a heated fluid conduit, such as a hose or tube, mightinclude disposing a semi-conductive material in the body of a fluidconduit and applying an electrical current across the body of the fluidconduit, heating the fluid conduit. In these embodiments thesemi-conductive material might comprise a semi-conductive carbon fibermaterial, which might be made up of carbon fiber threads or carbon fibertensile reinforcement material. If the conduit is a hose thesemi-conductive material might be disposed in the tube of the hose or inthe cover.

Thus, in accordance with embodiments of the present invention a heatedfluid conduit, such as a hose or tube, might have a body with asemi-conductive material disposed therein and might include means forcoupling an electrical power supply to each end of the conduit toprovide a voltage across the conduit and a current therethrough, heatingthe fluid conduit. This semi-conductive material might be asemi-conductive carbon fiber material, which might be made up of carbonfiber threads and/or carbon fiber tensile reinforcement material. In thecase of a hose, the semi-conductive material may be disposed in the tubeof the hose or in the cover of the hose.

Alternatively, in accordance with other embodiments of the presentinvention a method for heating a fluid conduit might comprise disposinga semi-conductive sleeve over the fluid conduit and applying anelectrical current to the semi-conductive sleeve, heating the sleeve andthe fluid conduit within. In accordance with various of theseembodiments the sleeve might comprise a fabric sleeve having carbonfiber threads which are at least semi-conductive.

Therefore, in other embodiments of the present invention a fluid conduitheating system might employ a semi-conductive flexible sleeve disposedover a fluid conduit and an electrical power supply coupled to each endof the sleeve to provide a voltage across the sleeve and a resultingcurrent through the semi-conductive sleeve, heating the sleeve and thefluid conduit. In particular, a first conductor can be conductivelycoupled to a first end of the sleeve and a second conductor conductivelycoupled to a second end of the sleeve, with the electrical power supplyconnected to the conductors to provide the voltage across the conductorsand the resulting current through the semi-conductive sleeve. In thisembodiment, one of the conductors, such as a wire, may be disposed alongthe sleeve, such as within the sleeve, such that the free ends of theconductors are at a same end of the sleeve, facilitating connecting theconductors to the power supply, such as through the electrical system ofa vehicle or piece of equipment. In accordance with various embodimentsthe sleeve is a fabric sleeve having carbon fiber threads which aresemi-conductive.

In some embodiments such a fluid conduit heating system might include aconductive ferrule disposed at each end of the sleeve in conductivecontact with the sleeve, with a first conductor conductively coupled toa first of the ferrules and a second conductor connected to a second ofthe ferrules, such that the electrical power supply may be connected tothe conductors to provide a voltage across the conductors and aresulting current through the semi-conductive sleeve.

As noted above, in various embodiments the electrical power supply maybe coupled to each end of the conduit or sleeve. However, in otherembodiments one terminal of the electrical power supply may be coupledto each end of the conduit or sleeve, and another terminal of theelectrical power supply may be coupled to the conduit or sleeve at apoint therebetween.

Also, in some embodiments of the present invention, a cover may bedisposed over a coupling fitted to an end of the conduit and/or over anend of a wire coupling the power supply to an end of the conduit, withthe wire passing through an opening in the cover. In some sleeveembodiments of the present conduits, systems or methods, the sleeve mayextend over the coupling and a cover may be disposed over the couplingand the sleeve extending over the coupling, as well as over an end of aconductor coupling the power supply to an end of the sleeve, again withthe conductor passing through the opening in the cover. Preferably, thecover insulates the coupling retaining heat generated. Also to retainheat, various embodiments may employ an insulating jacket disposed overthe conduit (and sleeve).

Advantageously, the present sleeve heating system affords an ability totailor the resistance per foot at assembly to meet heating requirementsneeded for individual conduit lengths. By using a sleeve with differentresistance levels, such as may be expressed in ohms per foot one maylower the resistance per foot for a longer length assembly.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present invention. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the invention as set forth in the appendedclaims. The novel features which are believed to be characteristic ofthe invention, both as to its organization and method of operation,together with further objects and advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. It is to be expressly understood, however, thateach of the figures is provided for the purpose of illustration anddescription only and is not intended as a definition of the limits ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form part ofthe specification in which like numerals designate like parts,illustrate embodiments of the present invention and together with thedescription, serve to explain the principles of the invention. In thedrawings:

FIG. 1 is a partially fragmented illustration of an embodiment of aheated fluid conduit of the present invention;

FIG. 2 is a partially fragmented illustration of an embodiment of afluid conduit heating system in accordance with the present invention;

FIG. 3 is a partially fragmented illustration of another embodiment of afluid conduit heating system in accordance with the present invention;

FIG. 4 is a partially fragmented illustration of yet another embodimentof a fluid conduit heating system in accordance with the presentinvention employing parallel heating circuits;

FIG. 5 is a perspective illustration of an embodiment of a cover for usewith various embodiments of the present fluid conduit heating system;

FIG. 6 is a perspective illustration of another embodiment of a coverfor use with various embodiments of the present fluid conduit heatingsystem;

FIG. 7 is a perspective illustration of yet another embodiment of acover for use with various embodiments of the present fluid conduitheating system; and

FIG. 8 is a partially fragmented side illustration of an embodiment of afluid conduit heating system in accordance with the present inventionemploying coupling covers.

DETAILED DESCRIPTION

In FIG. 1 a fragment view of an embodiment of heated fluid conduit 100is shown. Illustrated fluid conduit 100, a hose, is shown having body101 with semi-conductive material disposed therein. The semi-conductivemay take the form of “chopped” material 105, disposed in cover 108;woven or braided semi-conductive textile material 110 and/or 112;“chopped” material 115 and/or 117, disposed in intermediate hose layers116 and 118; and/or “chopped” material 120, disposed in tube 122. In theillustrated example of FIG. 1 this conductive material is intended to beillustrated as carbon fiber reinforcement material. Preferably, thesecarbon fiber threads act as tensile reinforcement material inillustrated hose 100. Electrical power, such as may be provided throughthe electrical system of a vehicle or piece of equipment may be suppliedto each end of conduit 100 such as through conductive wires, or thelike, electrically coupled to the hose to provide a voltage acrossconduit 100 and a current therethrough, heating fluid conduit 100 due toresistive conductivity provided by the semi-conductive reinforcementmaterial.

In accordance with the present invention the fluid conduit may be ahose, as illustrated. Alternatively, the fluid conduit may be a tube,such as a plastic tube, with the semi-conductive material disposed inthe body of the tube.

In accordance with other embodiments of the present invention a fluidconduit heating system (200), such as illustrated in FIG. 2, mightemploy semi-conductive sleeve 201 disposed over fluid conduit 202 andelectrical power supply 205, such as might be provided by a vehicle'selectrical system of the electrical system associated with equipmentusing the fluid conduit. This supply of electricity is preferablycoupled to each end of sleeve 201. For example, a first conductor, suchas illustrated wire 207, may be conductively coupled to first end 208 ofsleeve 201 and a second conductor, such as illustrated wire 210, may beconductively coupled to second end 212 of sleeve 201. To facilitate suchcoupling electrical connectors 215 and 217 may be disposed at respectiveends 208 and 212 of sleeve 201. The electrical power supply provides avoltage across conductors and 207 and 210 and the resulting currentthrough semi-conductive sleeve 201 causes the sleeve, and thereby theconduit within, to heat, due to the electrically semi-conductive natureof the material making up the sleeve. Preferably, conductive wires 207and 210 are disposed along the sleeve such that ends of the conductorsconnected to the power supply are at a same end of hose assembly 200(end 212 of sleeve 201 in FIG. 2). One, or both, of wires 207 and 210may be at least partially disposed either within sleeve 201, or in afurther outer covering of the hose, such as illustrated insulationsleeve 220. Insulation sleeve 220 may be made of any material whichsufficiently retains the heat generated by hose sleeve 201, such asclosed cell rubber foam.

Preferably, sleeve 201 is flexible. The sleeve might comprise a fabrichaving carbon fiber threads which are semi-conductive, similar to thehose of FIG. 1. The fluid conduit is illustrated as hose 202. However,the fluid conduit could be a tube, such as a plastic or metal tube.

An alternative embodiment of fluid conduit heating system 300 isillustrated in FIG. 3. In accordance with the present invention system300 might include semi-conductive sleeve 301, similar to sleeve 201above, disposed over fluid conduit 302. Conductive ferrule 315 or 317disposed at each end, 308 and 312 respectively, of sleeve 301 inelectrically conductive contact with sleeve 301. First conductor isconductively coupled to first ferrule 315 and second conductor 310 isconnected to a second ferrule 317. Electrical power supply 305,connected to conductors 307 and 310, preferably provides a voltageacross the conductors and a resulting current through semi-conductivesleeve 301. As with embodiment 200 above, sleeve 301 is also preferablyflexible and may comprise a fabric sleeve material having carbon fiberthreads which are semi-conductive. Also, similar to embodiment 200 thefluid conduit in system 300 may be a hose (as shown in FIG. 3), a metaltube, a plastic tube, or the like. Alternatively, an embodiment similarto that shown in FIG. 3 may employ non-conductive ferrules which mayhold the end of a conductor in electrically conductive contact with thesemi conductive sleeve or hose body, in provide a current through thesleeve or semiconductive body to heat the conduit in accordance with thepresent invention.

FIG. 4 is a partially fragmented illustration of an embodiment of fluidconduit heating system 400 employing parallel heating circuits. Parallelheating may be provided to any embodiment of the present invention bycoupling one terminal of the electrical power supply to each end of theconduit or sleeve, and another terminal of the electrical power supplyto the conduit or sleeve at a point therebetween. For purposes ofillustration, FIG. 4 applies such a parallel heating circuit embodimentto a sleeve embodiment similar to embodiment 200, illustrated in FIG. 2.However, more than the two illustrated parallel circuits could beprovided in accordance with the present systems and methods. In FIG. 4,semi-conductive sleeve 401 is disposed over fluid conduit 402 andelectrical power supply 405, such as might be provided by a vehicle'selectrical system of the electrical system associated with equipmentusing the fluid conduit is coupled to sleeve 401. One terminal of powersupply 405 is preferably coupled to each end of sleeve 401. For example,a first conductor, such as illustrated wire 407, may be conductivelycoupled to first end 408 of sleeve 401 and a second conductor, such asillustrated wire 409, may be conductively coupled to second end 412 ofsleeve 401, each of conductors 407 and 409 are preferably coupled to asame terminal of power supply 405. A third conductor, such asillustrated wire 410, may be conductively coupled to sleeve 401 at somepoint, such as mid-point 413, between ends 408 and 412. To facilitatesuch coupling electrical connectors 415, 418, and 417 may be disposed atend 408, midpoint 413 and end 412, respectively. The electrical powersupply provides a voltage across conductors 407 and 410, and also acrossconductors 409 and 410, in a parallel manner, the resulting currentsthrough semi-conductive sleeve 401 causes the sleeve, and thereby theconduit within, to heat, due to the semi-conductive nature of thematerial making up the sleeve. In a parallel circuit embodiment, theconduit is heated at a greatly accelerated rate. For example, a singlecircuit sleeve embodiment such as shown in FIGS. 2 and 3 might heatfluid in a conduit from −20° F. to 8° F. in 30 minutes, while a parallelcircuit embodiment such as illustrated in FIG. 4 might heat the fluid inthe conduit from −20° F. to 8° F. in less than 6 minutes.

Additionally, as mentioned above, more than two parallel circuits may beprovided in accordance with the present systems and methods. In suchembodiments the paired terminals of the power supply may be electricallyconductively coupled to the hose or sleeve in any number of pairs alongthe length of the hose or sleeve to provide the aforementioned multipleparallel circuits. Some of these embodiments might use switching, or thelike, to control operation of such circuits, or even the effectivenumber of circuits. For example, in the embodiment illustrated in FIG. 4an open switch in conductor 407 or 409 could disable the associatedcircuit. Additionally, or alternatively, a switch might open conductor410 and shunt the output therefrom to conductor 407 or 409 to provideconduit 400 a single restive heating circuit along its length.

FIGS. 5, 6 and 7 are perspective illustrations of embodiments a covers500, 600 and 700 for use with various embodiments of the present heatedfluid conduits and/or fluid conduit heating systems. FIG. 8 is apartially fragmented illustration of embodiment 800 of a fluid conduitheating system in accordance with the present invention employingcoupling covers similar to cover 500 and 600 illustrated in FIGS. 5 and6.

Covers 500, 600 and 700 provide protection and insulation forquick-connect couplings and wiring, such as conductors 807 and 810,associated with a heated fluid conduit in accordance with variousembodiments of the present invention. The embodiments of covers 500, 600and 700 shown are comprised of paired molded plastic parts, placedtogether to form a hard protective coverings for the couplings and thewiring. The illustrated covering embodiments each comprise two pieces,which are generally mirror images of each other, 501 and 502, 601 and602, and 701 and 702. The two halves may be adapted to “snap” together,thus alleviating any need for an adhesive or other cumbersome method ofjoining the two halves together. Alternatively, or additionally, the twopieces may be molded together in one mold with a small bit of plasticholding them together. This would allow the two pieces to be “hinged”over for installation.

Covers 500 and 600 are intended for use on straight couplings, whileembodiment 700 is intended for use on a ninety-degree elbow coupling.However, within the scope of the present invention, it is contemplatedthat any number of fitting configurations may be employed and covered ina similar fashion in a heated conduit system. On the internal surfacesof various embodiments of such covers, ridges may be employed to gripcorrugated tubing, other types of sleeves, a hose cover, or the like.These ridges may hold such a cover in place and help prevent exposure ofa heating sleeve.

Along with the two openings in the cover for the hose and coupling end(i.e. openings 503, 504, 603, 604, 703 and 704), there may be a separatethird opening (605 or 705) for wiring, such as for conductors 801, orthe like. As shown in FIG. 5, such a third opening may not be employedon every cover since the wiring for the hose may only exit from one endof a hose. On the angled versions of a cover, such cover 700, the wiringmay exit opposite the end of the coupling (i.e. in FIG. 7 the couplingmay extend out of opening 703, the hose out of opening 704 and wiringout of opening 705). Although wiring opening 605 in FIG. 6 is shown atan angle, forming a “Y” shape, a wiring opening out of a cover such ascover 600 may be disposed perpendicular to the coupling, resulting in agenerally “T” shaped cover. The inner surfaces of wiring exits 605 or705 may also have ridges, such as ridges 606 and 607 seen in FIG. 6, tograb onto any corrugated tubing, or the like, protecting the wiring.

Additionally, an access opening (510, 511, 610, 611, 710 or 711) may bedisposed on either side of a cover. These openings allow access to aquick-connect couplings disconnect button, or the like. This will allowa quick-connect couplings to disconnect from an adapter withoutrequiring the whole cover be removed. This increases the convenience andspeed with which a conduit employing the present heating system can beattached or removed from a particular piece of equipment. It is alsoanticipated that gaps may be defined in the internal ridges of the coverto allow for better air flow in the cover to enhance heating of thecoupling.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims. Moreover, thescope of the present application is not intended to be limited to theparticular embodiments of the process, machine, manufacture, compositionof matter, means, methods and steps described in the specification. Asone of ordinary skill in the art will readily appreciate from thedisclosure of the present invention, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the present invention.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps.

What is claimed is:
 1. A method comprising: disposing a semi-conductivematerial in the body of a fluid conduit; and applying an electricalcurrent across said body of said fluid conduit, heating said fluidconduit.
 2. The method of claim 1, wherein said semi-conductive materialcomprises semi-conductive carbon fiber material.
 3. The method of claim2 wherein said carbon fiber material compromises carbon fiber threads.4. The method of claim 2 wherein said carbon fiber material comprisescarbon fiber tensile reinforcement material.
 5. The method of claim 1,wherein said fluid conduit is a hose.
 6. The method of claim 1, whereinsaid fluid conduit is a tube.
 7. The method of claim 6, wherein saidtube is a plastic tube.
 8. The method of claim 1, wherein said disposingcomprises disposing said semi-conductive material in the tube of a hose.9. The method of claim 1, wherein said disposing comprises disposingsaid semi-conductive material in the cover of a hose.
 10. The method ofclaim 1, wherein said applying of said electrical current comprises:coupling a first terminal of an electrical power supply to a first endof said conduit; coupling a second terminal of said power supply to asecond end of said conduit; and providing a voltage, by said powersupply across the terminals.
 11. The method of claim 1, wherein saidapplying of said electrical current comprises: coupling a first terminalof an electrical power supply to each end of said conduit; coupling asecond terminal of said power supply to said conduit, between said ends;and providing a voltage, by said power supply, across the terminals. 12.The method of claim 1, further comprising insulating said conduit toretain heat.